That shouldn’t be an amazing fact, but it is: For the past four years, a federal judge has blocked the city from taking on any new recruits, claiming its hiring process — particularly, its entrance exam — was biased against minorities. The last time New York City hired a firefighter was in 2008.

Frankly, it’s a wonder how the city managed since then. But on Friday, Judge Nicholas Garaufis condescended to approve the city’s latest revision of its firefighter entrance exam. About time.

The city, it seems, managed to come up with a test whose racial results even Garaufis couldn’t reject.

Yet the idea that a test must meet racial quotas isn’t just odious; it raises questions about the test’s value in choosing the best candidates for the job. (A job, it’s worth noting, upon which millions of lives depend.)

Based on the score rankings for the exam in question, given last spring, the city expects 53 percent of its new hires to be white and about 43 percent black and Hispanic.

That’s a significant increase in minority hires over the last test. And all the parties in the lawsuit were fine with the new exam.

But Garaufis had no business declaring FDNY hiring discriminatory in the first place. And he’s grossly exceeded his authority in managing the case ever since.

Indeed, in his ruling Friday, he made sure to note that his green light for the latest test “does not end this case.”

New Yorkers can’t get rid of Garaufis quite yet.

Nor his special master, Mark Cohen, who’ll serve a (get this!) 10-year term, overseeing hiring. That’s as troubling as Garaufis’ years-long ban has been, if not more so.

Consider: Cohen, who’s already billed the city some $855,000, wants the FDNY to aggressively monitor communication among firefighters who disagree with Garaufis.

His demand came after gripes by the Vulcan Society, the black firefighter group that brought the suit, that FDNY fax machines sent out racially intimidating material.

Last year, another group of firefighters called Merit Matters e-mailed press releases decrying the judge’s rulings, which it feared might harm department quality. That group is run by Bronx Deputy Chief Paul Mannix, who offers his views of the case on the opposite page.

A city probe found no evidence that Merit Matters used FDNY fax machines to send the releases, but Cohen wants a crackdown on faxing and an “affirmative” statement that the department opposes Mannix’s views.

No new FDNY hires for years — but faxing policies are front and center.

It’s a stain on the courts that Garaufis has been allowed to remain on this case so long. His ruling Friday letting the city resume hiring is welcome, if overdue, news.

But New Yorkers just won’t be safe until he’s gone from this case altogether.